The present invention relates to a technology which is effective when applied to a transmission/reception switching circuit in a wireless communication system and further to the case where isolation between an antenna and a receiver circuit is thereby improved by reducing insertion loss. More particularly, the present invention relates to a technology which is effective when applied to a semiconductor integrated circuit formed with a transmission/reception switching circuit used in, e.g., a mobile phone, to a front-end module on which the semiconductor integrated circuit, a lowpass filter, an impedance matching circuit, and the like are mounted, and further to an electronic component for communication such as a power module obtained by mounting a high-output amplification circuit on the front-end module.
There have conventionally been dual band mobile phones each capable of handling signals in two frequency bands such as, e.g., a GSM (Global System for Mobile Communication) band ranging from 880 to 915 MHz and a DCS (Digital Cellular System) band ranging from 1710 to 1785 MHz. In recent years, there have also been demands for a triple band mobile phone capable of handling signals in, e.g., a PCS (Personal Communication System) band ranging from 1850 to 1915 MHz in addition to signals in the GSM and DCS bands and for a quad band mobile phone capable of handling signals in the EP GSM mode using a 800 MHz band and signals in the US GSM mode using a 850 MHz.
A conventional mobile phone has typically been constituted by: an electronic component termed a power module on which a semiconductor integrated circuit (generally termed an RF IC) having the function of up-converting and modulating a signal to be transmitted and down-converting and demodulating a received signal, a semiconductor integrated circuit (baseband IC) having the function of converting data to be transmitted to I and Q signals and restoring received data from the demodulated I and Q signals, an RF power amplifier and a bias circuit therefor, an impedance matching circuit, and the like are mounted; an electronic component termed a front end module on which a transmission/reception switching circuit, a lowpass filter, an impedance matching circuit, and the like are mounted; and the like.
Most of transmission/reception switching circuits used in conventional mobile phones have used diodes to reduce insertion loss. As an example of the invention relating to a front end module on which a switch circuit using a diode is mounted, there can be listed one disclosed in Patent Document 1. In the present specification, a plurality of semiconductor chips and discrete components which are mounted on an insulating substrate, such as a ceramic substrate with printed wiring provided on the surface or in the inside thereof, and which can be handled as if they compose a single electronic component with the individual components being combined by the printed wiring and bonding wires to perform a specified function will be termed a module.
[Patent Document 1] Japanese Unexamined Patent Publication No. 2003-051751